Type lever selection arrangement

ABSTRACT

AN ARRANGEMENT FOR SELECTING INDIVIDUAL TYPE LEVERS INTENDED TO PERFORM PRINTING, FROM A PLURALITY OF ADJACENT TYPE LEVERS WHICH ARE ASSEMBLED TO FORM A CONTINUOUSLY ROTATING RIM-SHAPED MAGAZINE. A MECHANICAL SELECTION IS EFFECTED BY A SHOOTING MAGNET ACTING UPON THE UPPER FREE END OF THE TYPE LEVERS. THE TIMING CONTROL FOR THE MAGNET IS DETERMINED BY A PULSE GENERATOR WHICH IS ARRANGED IN FRONT OF THE MAGNET A PREDETERMINED DISTANCE TO COMPENSATE FOR THE TIME REQUIRED FOR SELECTION AND REACTION OF A TYPE LEVER.

Oct. 26, 1971 F, GALASKE EI'AL 3,615,000

TYPE LEVER SELECTION ARRANGEMENT Filed April 2, 1969 6 SheetsSheet 1 Fig.7

INVENTORS FOL/(ER CALASKE CERHARD CRAP KARL HER/(L5 H LMUI' w. Scmauxvq ;/Z of ATT NEY pct. 26, 1971 GALASKE ETAL 3,615,000

TYPE LEVER SELECTION ARRANGEMENT Filed April 2, 1969 6 Sheets-Shee t 2 INVENTORS FOLKER QALASKE GERHARD cRAF KARL M'R/ BY ELMUT 9V. (f/IL INQ g H Oct. 26, 1971 F, GALASKE EIAL 3,615,000

TYPE LEVER SELECTION ARRANGEMENT Filed April 2, 1969 Y s Sheets-Sheet :5

Fig.3

INVENTORS FOLKER qALAsKE GER/{Alla CRAP KARL PIER/(LE LMUT w. SCH/l. nvc;

Oct. 26, '1971 GALASKE EI'AL I 3,615,000

TYPE LEVER SELECTION ARRANGEMENT Filed April 2, 1969 6 Sheets-Sheet 4.

Fig.4 V

ORNEY Oct. 26; 1971 GALASKE E'I'AL 3,615,000

TYPE LEVER SELECTION ARRANGEMENT Filed April 2, 1969 6 Sheets-Sheet 5 Fig.5

Fig.6

INVENTORS FOL/(ER CALASk (,ERHARD QRAF KARL MERKL' HELMUT SCH/LL/NC,

Oct. 26, 1971 F. GALASKE ETAL 3,615,000

TYPE LEVER SELECTION ARRANGEMENT Filed April 2, 1969 6 Sheets-Sheet 6 Fig. 7

. mvmons FOL/(ER .CALASKE can/mp0 GRAF KARL MERKAE HEL urw. 6C mun/ BY I ORNEY United States Patent 3,615,000 TYPE LEVER SELECTION ARRANGEMENT Folker Galaske, Gerhard Graf, Karl Merkle, and Helmut W. Schilling, Pforzheim, Germany, assignors to Interlnqagifonal Standard Electric Corporation, New York,

Filed Apr. 2, 1969, Ser. No. 812,636 Claims priority, application Germany, Apr. 27, 1968, P 17 61 288.3 Int. Cl. B41j 1/22 US. Cl. 197-18 11 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates to an arrangement for selecting individual type levers intended for striking the platen. A plurality of closely adjacent type levers which are formed in a continuously rotating rim-shaped maganine and are assembled into a unit forming the printing unit of a serial printer, and the selected type levers are deflected out of the normal path of rotation into a path extending in parallel therewith to accomplish the striking of the platen.

Serial printers employing a continuously rotating type lever magazine or assembly require complex selecting systems because at a high rotational speed with closely spaced type levers there must be insured a reliable selection of the type lever for accurately effecting the proper lever striking the platen.

One arrangement provides magnetic selection by causing a magnetic field moving with the type levers to cause the type lever to 'be deflected into the path leading to the striking of the platen.

A selecting device based on this principle, however, is very costly, and the required magnetic field for each lever represents another problem. The selecting arrangement according to the present invention provides a solution which is more easily implemented.

SUMMARY OF THE INVENTION According to the invention, there is provided a mechanical selection with a shooting magnet which suddenly acts upon the upper free end of a selected type lever. Positioned in front of the shooting magnet, in the direction of rotation of the printing unit, there is arranged a pulse generator which is caused to transmit pulses to a comparing counting circuit and control the shooting magnet. The center distance (distance from center to center) between the pulse generator and the shooting magnet corresponds to the angular path which is traveled by the upper end of a type lever during the period of time lapsing from the moment of a pulse transmission from pulse generator to the mechanical reaction of the shooting magnet to this pulse.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be explained in detail with Patented Oct. 26, 1971 reference to FIGS. 1 to 7 of the accompanying drawings, in which:

FIG. 1 shows in a partial sectional sideview, a printing mechanism with a selecting arrangement according to the invention;

FIG. 2 schematically shows the selecting arrangement in relation to the type lever magazine as shown in FIG. 1;

FIG. 3 is a longitudinal sectional view of one embodiment of the shooting magnet as used in the selecting arrangement according to the invention;

FIG. 4 illustrates a time-and-action diagram of the shooting magnet according to FIG. 3;

FIGS. 5 and 6 show two other hammer designs for the shooting magnet of FIG. 3; and

FIG. 7 shows a modified shooting magnet in a front and in a sectional side view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The printing unit 1 consists of a rim-shaped type lever magazine in which the type lovers 2 are pivoted on a common ring or annular axle 3 which is arranged concentrically in relation to the center point, and are guided in the sideways direction within two plate-shaped slotted disks 4 which are disposed in a mirror-imaged arrangement in relation to one another. When at normal, the type levers 2 rest on the through-going outer edge 4a of the upper slotted disk 4, thus assuming a substantially radial position in relation to the axis of rotation 1a.

The printing unit 1 forms part of a carriage device capable of being moved in the longitudinal line direction, parallel in relation to the platen 10. With the aid of gearing 5 this unit is continuously rotated via a stationary shaft 6.

Staggered by almost with respect to the printing point, there is arranged the selecting station 7 which is firmly connected to the carriage device.

In the course of the selecting process, the respective type lever 2 is deflected, as schematically shown in FIG. 2, out of the normal track of rotation and into a track lying above and which is determined by a guide '8 not shown in FIG. 1. In this swivel position, the selected type lever 2, with its projecting actuating member 2a, and in the course of the further rotation of the magazine, will enter the range of a printing cam 9 which is stationarily arranged on the carriage device, with this cam accelerating the type lever 2 so that it will strike the platen 10 at exactly the moment in which its printing movement extends orthogonally in relation to the longitudinal axis of the platen 10. The type lever 2 in rebounding subsequent to the striking is engaged via its projecting actuating member 2a 'by a reset cam (not shown) and is returned to the normal track of rotation.

The selecting station according to the invention, indicated by the reference numeral 7 in FIG. 1, is shown in the schematic representation of FIG. 2. It consists of a shooting magnet 11, a pulse generator 12, and a counting circuit 13 with a subsequently arranged pulse amplifier 14.

The shooting magnet 11 and the pulse generator 12, in accordance with the representation in FIG. 1, are arranged closely below the type levers 2 rotating in the normal track, with the pulse generator 12 being fixed at a certain distance X in the direction of the type lever magazine in front of the magnet 11.

The magnet 11 comprises a light-weight hammer 23 which, upon energization of the magnet, is rapidly moved upwards for shooting the type lever 2 as positioned thereabove from the normal track of rotation into the track determined by the guide 8 and as shown by the dot and-dash line.

This process requires a magnet whose hammer, is capable of being brought to a high speed over a short path, and the control of the magnet must be effected with a high degree of reliability, so that out of the plurality of closely adjacent type levers 2 only the one elected for striking, is hit by the hammer 23.

Accordingly, there is provided a pulse generator 12 which in a known manner is caused to transmit a pulse due to each type lever 2 passing its magnet poles 12a. These pulses are fed to a counting circuit 13. Based on a control signal arriving on line L which characterizes the type lever to be selected, this counting circuit determines which of the individual pulses is to be released for energizing the shooting magnet 11 via an intermediately connected pulse amplifier 14.

The center distance X (the distance from center to center) between the pulse generator 12 and the shooting magnet 11 is important. This distance X exactly corresponds to the path as traveled by the upper end of a type lever 2 during a period of time which is allowed to lapse from the moment of the pulse transmission by the pulse generator 12 to the mechanical reaction of the shooting magnet 11 to this particular pulse.

This arrangement has the advantage that divisional differences between the individual type levers have no influence upon the exactness of the selection and that speed variations, or variations in the number of rotations of the type lever magazine, are not critical within relatively wide limits. This is because there are not any variations within the range of the small distance X between the generator 12 and the magnet 11 which enables the use of normal, non-regulated motors for the driving input.

FIG. 3 shows an embodiment which is capable of meeting these high magnet requirements. The most substantial constructional feature comprises the lift member which is subdivided into a plunger 20 to be actuated by a magnet and a separate hammer 23, with the mass of the plunger 20 in forming one unit with armature plate 19, being in a relatively large proportion in relation to that of the hammer 23.

As shown in FIG. 3, the actual magnet is surrounded by a housing 15 and is firmly connected therewith by means of screws 15a. The magnet consists of a yoke plate 16 provided with a central bore, to which there are screwed the pole shoes or pieces 17 which are provided with the excitation windings 18. At a distance S -I-S (FIG. 4) the inwardly angled-off and surfaceground ends of the pole shoes 17 are opposed by the armature plate 19. This armature plate 19 which is designed to have the shape of a round disk carries in its center the plunger 20 which is firmly connected therewith, and finds its sideways guidance in a pot-shaped adjusting screw 27 which is arranged in the housing 15, and is adjustable vertically in relation to the adjusting direction of the plunger stroke S +S Within the lower part of its pot-shaped recess the adjusting screw 27 is provided with a ring-shaped flexible filler 28 which is adapted to the shape of the armature plate 19 thus serving as a support for the latter when at normal. The setting of the screw 27 is secured by a locknut 29.

The plunger 20 projecting through the central bore of the yoke plate 16 has its upper guidance in an adjusting ring (set collar) 22. Between this adjusting ring 22 and a collar portion 20a of the plunger 20 there is arranged a relatively weak compression spring 21 which is provided above all for securing the defined normal position of the unit consisting of the armature plate and the plunger, but which also serves to dampen the bouncing ((chatter)phenomena as appearing subsequently to an actuation.

Besides guiding the plunger 20 the adjusting ring (set collar) 22 serves above all the adjustment of the idle stroke S between the face side of the plunger 20 which, for reasons of achieving an improved stroke exchange,

4 is slightly arched, and the plane bottom side of the hammer base 23a which, when at normal, rests on the adjusting ring 22.

The normal position is secured by a compression spring 24 acting upon the flange-like hammer base 23a, finding its abutment on a ringnut 26. The latter at the same time, constitutes the upper guide for the hammer head 23b. At the bottom the hammer 23 is guided via the base portion 23a in a distortion proof manner in a spacer ring 25. At the same time this ring 25 by its thickness, determines the maximum stroke S +S (FIG. 4) of the hammer 23.

The mode of operation of this magnet will now be explained in detail with reference to the diagram shown in FIG. 4. Based on the selecting arrangement as described with reference to FIG. 2, it is assumed that at a time position TX, fixed within the selection cycle, a rectangular pulse of the duration t is applied to the excitation windings 18 of the armature. The armature/ plunger unit 19/20 which is thus caused to attract travels the path S during this period of time, and at point A reaches the speed or velocity v1, where the plunger 20 hits the hammer 23. The almost flexible stroke exchange (exchange of impact) taking place now, causes in a wellknown way the hammer 23 to be moved rapidly upwards at an increased speed owing to its mass which is substantially smaller than that of the armature plunger unit 19/ 20.

Whereas the armature/ plunger unit 19/20, until meeting against the armature plate 19, only performs the slight excessive stroke S against the pole-pieces 17 and thereupon, owing to the lack of energization, returns to normal, the hammer 23 is rapidly moved upwards at an almost constant speed v2 for hitting at the end of the selection stroke 5;, at point B the type lever 2 to be lifted. There is again performed a further stroke exchange during which, due to the mass ratio which is now inverted, between the hammer 23 and the type lever 2, the entire kinetic energy as stored in the hammer is transferred to the type lever. The mass of the hammer 23 is chosen so that the stroke or impact energy is sufficient for reliably lifting the reespective type lever 2 into the track determined by the guide 8 (FIG. 2), with the hammer immediately after the stroke exchange, will return to normal. The hammer 23 is prevented from interferring with the rotating type levers of the successively following type levers and from damaging the entire arrangement.

For the case shown in FIG. 6, it might be that the hammer injects between two adjacent type levers 2. In this case, no stroke exchange take place at point B of FIG. 4, thus permitting the hammer 23 to inject into the rotational track of the type levers up to the backstop of the hammer base 23a against the bottom edge of the ringnut 26 (FIG. 3 at point C (FIG. 4) by the amount of excessive stroke S During rebouncing, it would then return to normal in accordance with the dashlined curve.

It must be expected that the hammer 23 will not always exactly meet in the center of the selected type lever 2, and that there may happen an advancing or lagging displacement. In view thereof the hammer head 23a will have to be given a shape corresponding to these conditions in order to avoid a double selection or damage to the total arrangement.

FIG. 5 shows one type of a hammer 23 to be used in cases where a large number of type levers 2 is assembled in one printing unit 1, so that the distance between two adjacent type levers 2 becomes very small. In this particular case the hammer head 23b should have a width which is greater than the distance from type lever to type lever. Moreover, the face side 230 of the hammer head 23b is inclined throughout the entire width and in opposition to the direction of rotation of the printing unit. In the extreme case as shown only the first type lever 2 is selected, whereas the second one remains unaffected due to the inclined face side. In the way described hereinbefore, hammer 23 performs a rearward movement immediately after the stroke exchange (exchange of impacts).

FIG. 6 shows another hammer design which is suitable for use in cases where the distance between the type levers is so large that a hammer designed according to FIG. would become too wide and, consequently, too heavy. In this case the hammer head 23b is made narrow to inject, in the shown extreme case, between two successively following type levers without touching one of them. Since the stroke S is very small and the hammer, according to the description with reference to FIG. 4, is rapidly moved back into the normal position, it will only remain within the range of rotation of the type levers for a very short period of time. This period of time, however, might be sufficient to cause the subsequently following type lever 2 to run into the hammer head 23b. To avoid such a positive connection between the two parts, which is likely to cause damages, the hammer head 23b is provided on the respective side with an inclined portion 23d extending deep enough to correspond to the maximum immersion depth S If a hammer 23 strikes a type lever 2 within the range of this inclined portion 23d, the type lever 2 will slide away upwardly, or else will push the hammer 23 away downwardly due to the lower mass thereof. Since the forces acting upon the type lever 2 in the selecting stroke direction are small in any case, there will not be effected a deflection of the respective type lever.

The subdivision into plunger 20 and hammer 23 in connection with the idle stroke S has the added advantage that, in the case of permanent energization of the magnet windings 32, it cannot happen that the hammer 23 will remain within or come to a standstill within the range of rotation of the type levers 2. In this case the hammer 23, because the plunger remains in its attracted position, will assume a normal position which is slightly lifted by the excessive stroke S in which between the face side of the hammer and the bottom edge of the type lever there is a sufficient distance or spacing, as indicated in FIG. 4.

A modified embodiment of the shooting magnet 11 is shown in FIG. 7. In the upper part of a U-shapedly bent housing 30, a magnet yoke 31 which is of a U-shaped design is firmly fixed by a screw arrangement. On the yoke ends which are directed downwardly there are arranged the magnet windings 32. A bearing block 36 is positioned in the rear part of the housing 30, and serves as atensioning block for a flat spring 34 which, in the width of the yoke, projects forwardly out of the housing 30, and is tapered towards its free end on which a hammer head 35 is mounted. In order to keep the mass of the fiat spring 34 small, it is made of a relatively thin material. For achieving the necessary rigidity the longitudinal edges 34a thereof are turned upwardly with the exception of a rear portion near the bearing block 36. In alignment with the yoke ends, an armature plate 33 is mounted on the fiat spring 34. The necessary spacing from the yoke poles is capable of being adjusted via a support 37 which is provided with a flexible backstop 38 on which the flat spring 34 rests in a plan-parallel fashion when at normal, and almost over its entire length under a slight bias (pretension). This bias is adjusted by turning the bearing block 36 about its longitudinal axis.

When using this type of magnet in the arrangement according to FIG. 2, it is equivalent to that of the magnet shown in FIG. 3. Upon energization of the magnet windings 32 the armature plate 33 is accelerated until meeting against the backstop, in the course of which the thin flat spring 34 due to the soft bending range near the bearing block 36, will have little retarding effect. Shortly in front of the backstop of plate 33 this spring reaches its highest speed. According to the lever ratio azb, the speed of the hammer head 35 at the end of the flat spring 34 is higher. At high speed, the free end of the fiat spring 34 oscillates with the hammer head 35, subsequently to the striking of the armature plate 33, still further upwardly against the yoke poles. Within this range of oscillation, the hammer head 35 meets the type lever 2. The exchange of stroke or impact occurring will exect in the way described hereinbefore the lifting of the respective type lever 2, so that the lever will enter the track as determined by the guide 8.

Touching between the hammer head 35 and the type lever 2 only takes place within the range of the overoscillation, and a permanent energization of the magnet windings 32 will also in this case not cause any mechanical damage of the total arrangement.

After the effected stroke exchange (exchange of impacts) the front end of the flat spring rebounds with a certain acceleration which is due to the spring action. The hammer head 35 then is only positioned within the range of rotation of the type levers 2 for a very short period of time, so that normally there cannot be effected a selection of more than one type lever. When compared with the hammer 23 of FIG. 3, however, the flat spring with the hammer head represents a greater mass which is not fully retarded by the stroke exchange and will inject into the track of the type levers for a short period of time. In order to provide for all eventualities, it is necessary to provide the hammer head 35 with the shape as shown in FIG. 6.

In order to keep the entire selecting process as short as possible, it is necessary for the flat spring 34 to be dampened as quickly as possible with respect to its oscillation, which may be effected by the damping flexible backstop 38. A further damping of the oscillation can be achieved by the magnet windings 32 remaining energized until the flat spring has been moved back after the stroke exchange (exchange of impacts), thus restricting the flat spring 34 in its movement.

We claim:

1. In an arrangement for selecting individual type levers, to effect printing, out of a plurality of closely adjacent type levers radially assembled in a continuously rotating rim-shaped magazine, with the free end of each type lever being remote from the axis of rotation of the magazine, and forming one unit constituting the printing unit of a serial printer, and in which the selected type levers are deflected out of their normal track of rotation and into a parallel extending track to cause striking of the platen, the improvement comprising:

a hammer-actuating solenoid assembly (11) for effecting the selection of the type levers, said assembly (11) acting upon the free end of the selected type lever (2), and including a lifting magnet having a lifting member, said lifting member being subdivided into a plunger (20) forming a single unit with an armature plate 19), and a separate hammer (23), said lifting member having a spacing (S1) provided between said plunger (20) and said hammer (23) in the normal condition which is less than the operating stroke (SH-S2) of said plunger (20), and wherein said plunger (20) forming the single unit with the armature plate (19) has a mass of predetermined larger proportion relative to the mass of the hammer a pulse generator (12), arranged in front of said assembly (11) in the direction of rotation of the printing unit, for transmitting pulses in accordance with the succession of the passing type levers (2); and

a comparing counting circuit (13), coupled to said assembly (11) and to said pulse generator (12) for controlling said assembly (11) in response to the pulses from said generator (12), wherein the center distance (X) between said pulse generator (12) and said solenoid assembly (11) is substantially equal to the angular path which is traveled by the free end of a type lever (2) during a period of time lapsing from the moment of a pulse transmission of said pulse generator (12) to the mechanical reaction of said solenoid assembly (11) to said pulse transmission.

2. The arrangement according to claim 1 further including a spacer ring for guiding said hammer (23), the thickness of said ring (25 being determinative of the operating stroke (S3 +S4) of said hammer, and wherein the spacing (S1) of said hammer (23) from the face side of said plunger (20) is adjustably controlled by a set collar (22) guiding said plunger (20), in connection with a ringnut (26) guiding the hammer head (23b).

3. The arrangement according to claim 1, wherein the mass of said hammer (23) is a predetermined amount greater than that of a type lever (2), with the predetermined relative masses of said hammer (23) and type lever (2) being such as to insure that the kinetic energy, as transferred via the hammer (23) from the plunger (20) in the course of the stroke exchange, is suflicient for lifting the type lever (2) into the path leading to the printing.

4. The arrangement according to claim 3 further including a pot-shaped adjusting screw (27) for adjusting the operating stroke (S1 +S2) of said plunger (20), said screw (27) simultaneously providing the sideways guidance of said armature plate (19), and being provided with a flexible filler (28) which is adapted to the surface shape of said armature plate (19), and is determinative of the normal position thereof.

5. The arrangement according to claim 4 further including first and second compression springs (21, 24) for securing said plunger (20) and said hammer (23) respectively.

6. The arrangement according to claim 1 wherein the width of said hammer head (23b) is greater than the division spacing of said type levers (2), and wherein the face side (232) of said hammer head (23b) is inclined in opposition to the direction of rotation of said printing unit (1).

7. The arrangement according to claim 1 wherein the width of said hammer head (23b) is narrower than the spacing between two successively following type levers (2), and wherein the rear edge thereof is inclined in accordance with a maximum injection depth.

8. The arrangement according to claim 7 wherein said hammer head (23b), in the case of a permanent energization of said solenoid, is arranged to assume a position outside the circular path of said type levers (2).

9. The arrangement according to claim 1 wherein said a hinged armature type of magnet, with the armature plate (33) thereof forming one unit with a biased flat spring (34) which is supported on one side, with a hammer head (35) being mounted to free end thereof.

10. The arrangement according to claim 9 further including a magnet yoke (31) having a U-shaped design and arranged transversely in relation to the longitudinal expansion of said flat spring (34), and wherein said flat spring (34) is turned upward at its longitudinal edges (34a).

11. The arrangement according to claim 10 further including an adjustable flexible backstop, wherein said fiat spring (34) in the normal condition rests with its entire length and width on said adjustable flexible backstop (38).

References Cited UNITED STATES PATENTS 2,369,433 2/1945 Casey 197-18 3,072,045 1/1963 Goin 101-93 3,282,206 11/1966 Eckert 101-93 3,289,805 12/1966 Kleinschmidt et a1. 197-18 3,355,001 11/1967 Reed et a1 197-18 3,417,690 12/1968 Clark et al 101-93 3,417,847 12/1968 Fleischer et al. 197-18 3,420,349 1/1969 Kupfmuller 197-18 X 3,426,675 2/1969 Dalton 101-93 3,459,126 8/1969 Nyman 10 1-93 3,473,466 10/1969 Thayer 101-93 EDGAR S. BURR, Primary Examiner US. Cl. X.R. 

